drm/i915/kbl: Add Kabylake GT4 PCI ID

drm/i915/kbl: Add Kabylake GT4 PCI ID

v2: (Rodrigo) Rebase after commit a728fae29
    ("drm/i915: remove an extra level of indirection in PCI ID list")

Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Deepak S <deepak.s@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1446060072-19489-1-git-send-email-rodrigo.vivi@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>